docs: def _process_flags(self):
          """
          Override to add an additional check after processing the flags: when
          there are no flags left after argument parsing, then it means we'll be
          editing the whole todo.txt file as a whole and therefore we're not in
          multi mode.
          """
          super()._process_flags()
  
          if len(self.args) == 0:
              self.multi_mode = False